The allocolchicinoids, or allocolchicines (the terms hereafter used interchangeably), are a well-recognized series of natural products and natural product derivatives based on a dibenzocycloheptane ring system, and which inevitably possess a 9,10,11-trialkoxy substitution pattern in the A ring. Many of the individual compounds of this class are known to have antitumor properties against a variety of cancer cell lines. Unfortunately, these compounds tend to be cardiotoxic, which apparently renders them inapplicable for cancer treatment. For example, ZD 6126 (N-Acetylcolchicinol dihydrogen phosphate) failed in Phase 2 clinical testing because of this cardiotoxicity.
